The present invention relates to check valves and, more particularly, to in-line check valves for use in fire protection systems
A typical fire protection system includes a riser or supply pipe connected to a water main. Branches are connected to the riser and extend throughout the building to the areas to be protected. Drop pipes are secured to the branches. Each drop pipe supports an automatic sprinkler head. Each sprinkler head opens or releases when a predetermined temperature is reached, which indicates a fire condition. Upon opening, water or other fire suppression fluid flows to the sprinkler heads and to the area of fire. The systems also include check valves in the supply piping. The check valves, which permit flow in one direction, generally include a seat and a check valve element held against the seat by a spring. A predetermined pressure differential across the valve is necessary to permit flow through the valve. The flow loss or pressure drop across the valves should be taken into consideration when designing the system to insure a proper supply of fluid to the sprinkler heads. Booster pumps may be included to insure an adequate supply to the sprinkler system.
In addition, existing check valves present difficulties with field maintenance and installation. Certain types of existing check valves may be subject to fouling from debris in the water or supply line. The debris may prevent a check valve from fully opening or closing.
A need exists for a check valve having a reduced flow loss or pressure drop resulting in increased flow and which includes a large flow area to prevent fouling. In addition, a need exists for a check valve which significantly eases installation and field maintenance.